Ramsey County prosecutors said no criminal charges will be filed against the St. Paul police officer who fatally shot a Maplewood man who shot him in the leg in December.

The Ramsey County Attorney's Office announced Thursday that Michael Tschida with the St. Paul Police Department was justified in fatally shooting 24-year-old Brandon DaleShaun Keys on Dec. 7. Prosecutors reached their decision after reviewing witness statements, DNA, and other evidence collected by investigators with the Minnesota Bureau of Criminal Apprehension.

"The truth is that all too often police officers are called to dangerous situations having to place their lives on the line to protect those who call upon them and our community," Ramsey County Attorney John Choi said in a memo released Thursday. "We should appreciate this act of public service while also recognizing the deep loss that is felt by the family and friends of Mr. Keys."

Choi's office expects the BCA will release public portions of its investigation soon.

According to police, just after 2 p.m. on Dec. 7, officers were called to the area of Marshall and Cretin avenues in St. Paul. A 911 caller said she had an order for protection against Keys, who was following her as she drove in the area.

"She reported the man was intentionally driving his vehicle into hers, was armed with a handgun and had broken a window out of her vehicle," the department's account said.

Keys shot at Tschida after being ordered to the ground, striking the 14-year law enforcement veteran in the leg.

Tschida ducked behind his vehicle before standing to return fire, striking Keys.

Witnesses heard "a bunch" of gunshots during the confrontation. One witness saw Tschida limp across the road as a woman cried and screamed for Keys.

"She just wailed for like half an hour," Cara Corey said the day of the shooting. "She kept saying, 'They shot him in the head. What am I going to tell my kids?'"

Emergency crews took the injured Keys to Regions Hospital in St. Paul; he died the next morning. Tschida was treated and released from the same hospital the night of the shooting.

Body camera footage released five days after the shooting showed the moment Tschida ordered Keys to the ground before volleys of bullets flew. Authorities also released the transcript of the 911 call leading to the encounter. That caller said Keys was armed and broke the windows of her van.

Keys was due in Hennepin County District Court that week for a hearing about a two-year order for protection by a 38-year-old woman who shares a 5-year-old child with him, according to court records. It's unclear if she is the same woman involved in the shooting.

Star Tribune staff writers Louis Krauss and Paul Walsh contributed to this story.